Generator brush with condition indicator



Patented Oct. 5, 1954 GENERATOR BRUSH WITH CONDITION INDICATOR Earl D. Lykins, Huntington, W. Va.

Application May 8. 1951, Serial No. 225,189

1 Claim. 1

This invention appertains to improvements in electrical signalling devices and particularly relates to an alarm for use in indicating predetermined wear of a generator brush.

A primary object of this invention is to obviate the necessity for inspection of generator brushes and to prevent generator failure, due to open or partially open circuits, caused by excessive brush wear.

Another object of this invention is to provide signal means for indicating excessive or predetermined wear of a generator brush and to indicate the brush wear considerably before brush failure.

These and ancillary objects and structural features of merit are attained by this invention, the preferred embodiment of which is set forth in the following description and illustrated in the accompanying drawing, wherein:

Figure 1 is a cross sectional view of a conventional generator, with a signalling device, constructed in accordance with the principles of this invention, being operatively associated with the brush clip;

Figure 2 is a top plan view of the clip;

Figure 3 is a longitudinal vertical sectional view taken on line 3-3 of Figure 2;

Figure 4 is a top plan view of the clip, with a contact member for the indicating circuit being mounted thereon; and,

Figure 5 is an elevational view of the insulative brush assembly to which the contact member for the signalling circuit is attached.

The primary purpose of this invention is to provide an alarm or a signal for indicating a predetermined wear of the brush of the insulated brush assembly or rigging, since in the majority of cases the insulated brush is subjected to more wear than the grounded brush. However, alarm means may be operatively associated with both the insulated brush and the grounded brush by use of a conductor carrying current to the grounded brush assembly through the insulated clip thereof, separate signalling devices being employed for each of the brushes, so that each signalling device would be individually controlled by the particular brush assembly to which it is connected.

Generally, a resilient contact member is provided and is carried by the spring urged clip of the insulated brush rigging, the clip bearing on the brush to retain the brush in wiping contact with the commutator and the contact member being so disposed that it has a free end, which is engageable with the brush holder, after a predetermined wear of the brush. A grounded electrical circuit, including a signal, either visible or audible, is connected to the contact member and, upon engagement of the contact member with the brush holder, the signal is operative to indicate the wear of the brush.

With continued reference to the accompanying drawing, a conventional two brush generator [0 is illustrated, the same including a commutator i2 and a grounded brush rigging or assembly M.

The alarm device, provided by this invention, is illustrated as operatively associated with the insulated brush assembly l6 and particularly attached to the clip I8. The clip I8 is formed with a pair of parallel apertured ears 2!! and 22, which are journaled on the post 24, with a spring being coiled on the post and engageable with the body portion 26 of the clip to urge the tongue 28 of the clip into engagement of the outer end of the brush 30 for retaining the brush in wiping contact with the commutator.

In accordance with this invention, an opening 32 is formed in the body portion of the clip, intermediate the cars 20 and 22 and an insulated bushing 34 is seated in the opening for the reception of a stud or rivet 36. One end of a resilient contact member or strip 38 is affixed by the rivet to the body portion of the clip and on the opposite side of the body portion, the end 40 of an insulated conductor 32 is aflixed to the rivet.

The contact member 38 underlies the body portion of the clip and is formed with a downwardly extending free contact end Ml, which is engageable with the end 46 of the contact holder,

upon a predetermined or excessive wear of the brush 30, as can be seen in Figure 1, where the contact end 44 of the contact member is illustrated in spaced relation to the end 46 of the brush holder.

The conductor 42 is grounded as at 48 and a lamp 50 is connected to the conductor so that when the contact member 44 engages the end of the brush holder, the current from the brush 30 will flow through the conductor to the ground 48 and illuminate the lamp 5%. The lamp 5!) is preferably mounted, with respect to an automotive vehicle, on the dashboard of the vehicle,

3 be provided with signalling means, this being accomplished by a conductor carrying current to the grounded brush from the insulated brush assembly and necessitating the use of two lamps 50 or two signalling devices, instead of one. In such a case, each lamp 50 or signalling element would be controlled by the particular brush to which it is attached or connected, thus affording protection against damaging wear to either brush.

However, in most cases, wear occurs on the insulated brush 30, rather than on the grounded brush 52 and, therefore, one alarm or signalling device for the brush 30 will generally be found to be sufiicient.

Obviously, the lamp 50 will be constantly illuminated, as long as the contact member is in engagement with the brush holder and the generator will continue to charge, until the brush 30 becomes excessively worn. In this fashion, the alarm, indicating a predetermined wear on the brush, is given to the driver of the vehicle but the generator will continue to charge, so that sufficient time is afforded to efiect a brush change.

Having thus described this invention, what is claimed is:

In an electrical generator brush assembly, a conductive brush holder having outer and inner ends, a laterally extending conductive portion on said brush holder, a brush mounted on said brush holder for endwise movement relative to said brush holder, said brush having an end exposed at said outer end of the brush holder and another end projecting beyond said inner end of the brush holder for engagement with a generator commutator, an arm extending along said laterally extending portion on the brush holder, said arm having a laterally inward end overlying the outer end of the brush holder and engaging the adjacent end of the brush, said arm having an outer end pivoted on said laterally ex-' tending portion, spring means acting between said laterally extending portion and said arm and pressing the arm in an inward direction to engage the brush with a commutator, said laterally projecting portion on the brush holder having a fixed lateral contact finger thereon, said contact finger being located close to the brush holder and being spaced inwardly from the outer end of the brush holder, and a leaf spring contactor at the inward side of and extending along said arm, said contactor leaf spring having a free end overlying and normally spaced outwardly from said contact finger and another end, and insulated means fixing the other end of the leaf spring contactor to said arm at a point adjacent to the outer end of the arm.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 942,264 Kimble Dec. '7, 1909 1,295,860 Dean Mar. 4, 1919 2,146,357 Schweikle Feb. 7, 1939 2,193,172 Hills Mar. 12, 1940 FOREIGN PATENTS Number Country Date 88,470 Austria May 26, 1922 560,232 Germany Sept. 30, 1932 590,950 Germany Jan. 13, 1934 

